This invention relates to a method and apparatus for generating singlet delta oxygen. In a more particular aspect, this invention relates to a method and apparatus for the generation of oxygen in the excited singlet delta electronic state which in turn can be used in high energy chemical lasers. This type of generation system finds particular utility as a means for producing an electronically excited species for lasing systems which must be compact, portable, safe and subject to exposure to low gravitational fields.
Several practical applications exist in which lasers are used in heating, navigation and communication systems. These devices employ an optically active media from which a laser beam is extracted. The beam is generated by means of a population inversion consisting of an unstable abundance of molecules having excited high energy electronic states which release photons as they decay to the equilbrium lower energy states of the optically active media.
In high energy chemical lasers, the excited electronic states are generated by a chemical reaction. For example, one such reaction involves the use of excited molecular oxygen, hereinafter referred to as O.sub.2 (.sup.1 .DELTA.), in combination with an optically active media or lasing substance, such as iodine or fluorine. These lasers have been found to be very useful and the increased interest in their use has spawned a considerable research effort in an attempt at improving their performance characteristics, especially in the area of materials supply. However, a number of problems in the generation, storage and maintenance of the gaseous reactant materials required to produce the necessary population inversion has limited the use of these chemical lasers in military and airborne applications.
One method presently in use for generating a stream of O.sub.2 (.sup.1 .DELTA.), involves a chemical reaction between chlorine gas and an alkaline solution of hydrogen perioxide. The excited oxygen so generated, can then be added to a suitable lasing medium and the mixture passed through an optical resonator to bring about a lasing action. Specific details of such a method are disclosed in U.S. Pat. No. 4,246,252, issued Jan. 20, 1981 to McDermott et al.
The prior art method referred to above, however, has several inherent problems which have prompted the study of alternate systems for generating O.sub.2 (.sup.1 .DELTA.) in a more efficient manner. One such problem is that as the device is scaled to a larger size, the volume of hydrogen peroxide required becomes quite large. Since hydrogen peroxide is a monopropellant with an explosive TNT equivalent of 0.40, scaling the device to a large size presents a hazard. Another problem which occurs with a bubbler type apparatus is the creation of a variation in the yield of O.sub.2 (.sup.1 .DELTA.) as a function of time. A byproduct of the oxidation reaction is HCl. To consume the acid, a base is added to the peroxide. As the base is used, the solution becomes acidic and the production of O.sub.2 (.sup.1 .DELTA.) diminishes. Further, the salt produced in the neutralization builds up in solution. Also, the use of a bubbler type apparatus in low level gravitational fields or in areas of high vibration is difficult in that the solution cannot be retained in the reactor.
With the present invention, however, it has been found that the problems associated with the prior art can be overcome by the discovery of a device and method which is capable of producing the desired O.sub.2 (.sup.1 .DELTA.) continuously, safely and reproducibly.